Modelling interactions between waves and diffused interfaces

When simulating multiphase compressible flows using the diffuse-interface methods, test cases presented in literature to validate modellings with regard interface problems are always textbook cases: interfaces sharp and simulations therefore easily converge exact solutions. In real problems, it is rather different because waves encounter moving which consequently have already undergone effects of numerical diffusion. Numerical solutions resulting from interactions diffused never been precisely investigated for good reasons, results obtained extremely dependent on model used. Precisely, well-posed models present similar important issues when such an interaction occurs, coming appearance a wave-trapping phenomenon. To circumvent those issues, we propose use thermodynamically-consistent pressure-disequilibrium finite, instead infinite, pressure-relaxation rate overcome difficulties inherent computation these interactions. Because original method solve this only enables infinite relaxation, new allowing as well finite relaxation rates. Solutions modeling examined compared literature, particular study shock water–air interface, but also helium–air tubes, spherical nonspherical bubble collapses.